Hypersensitivity pneumonitis due to occupational inhalation of fungi-contaminated corn dust

Hypersensitivity pneumonitis or extrinsic allergic alveolitis can be defined as a lung disease caused by a wide group of antigens that reach the lung by inhalation of organic and/or inorganic dust of various sources. The dust of the stored maize corn has been reported as cause of respiratory symptoms. During the storage process, maize corn dust can be contaminated by moulds and thermophilic actinomycetes, which have not been described until now as the causing antigens of these symptoms. We present a case of occupational hypersensitivity pneumonitis in an agricultural worker who cultured and stored maize corn. Clinical findings, precipitating antibodies, and evolution after having removed him from his work, confirmed the diagnosis. In our case, Aspergillus species contaminating the maize corn dust are probably the antigens that caused the disease.

[Estimation of transmission hazard of Leptospira Sp. infections in 2 groups of people]

The aim of the study was to determine the possible risk of the leptospiral transmission from animals to humans. 457 humans (both men and women) were divided into 2 groups: 1) of possible high risk infection consisted of people dealing as farm workers with cattle and pigs 2) of possible low risk infection consisted of people selected randomly. The animals on the farms were previously tested and found positive. All sera were examined using micro-agglutination test (MAT) with a battery of 18 serovars. The statistical evaluation of the results was performed using chi 2 test. The infection rate in I group was 13.79% and in II group was 1.5%. (p < or = 0.001). Sera of I group reacted with 7 serovars (sejroe, bratislava, canicola, tarassovi, bataviae, celledoni, patoc) and of II with 3 (hebdomadis, sejroe, hardjo). The infection rate in the group I was over 9 times higher than in group II. Thus dealing with infected animals is a high risk factor.

Primary sensitization to sweet bell pepper pollen in greenhouse workers with occupational allergy

BACKGROUND

In a previous investigation, a high prevalence of allergy to sweet bell pepper pollen was found among exposed horticulture workers. Allergy to plant-derived food is often the consequence of primary sensitization to common pollen allergens.

OBJECTIVE

We therefore investigated the cross-reactivity between sweet bell pepper pollen and pollen from grass, birch or mugwort.

METHOD

We selected 10 sera from greenhouse workers who had, besides specific IgE against sweet bell pepper pollen, also IgE to grass, birch or mugwort pollen. Cross-reactivity was tested by the inhibition of IgE binding to solid-phase coupled sweet bell pepper pollen extract. The 10 sera were also analysed for IgE binding to sweet bell pepper pollen by immunoblotting.

RESULTS

With these sera, no or small inhibition of IgE binding to sweet bell pepper pollen extract was observed with grass, birch and mugwort pollen. With immunoblotting, major IgE-binding structures were seen at 14, 29 and 69 kDa in sweet bell pepper pollen extract.

CONCLUSION

The results of our study demonstrate that sweet bell pepper pollen contains allergens that have no or limited cross-reactivity with common pollen allergens. With sera from the 10 patients tested, sensitization to sweet bell pepper pollen was not the consequence of primary sensitization to common pollen allergens.

The respiratory inflammatory response to the swine confinement building environment: the adaptation to respiratory exposures in the chronically exposed worker

Swine confinement facility workers often develop respiratory problems secondary to their work, including the asthma-like syndrome, exacerbation of underlying asthma, chronic bronchitis, and mucous membrane irritation syndrome. Organic dust toxic syndrome is seen in these workers as well. Swine confinement barns are characterized by the presence of multiple factors that can cause respiratory tract and systemic inflammation symptoms, including dust, endotoxin, and ammonia. Investigators have found evidence of inflammation characterized by increased numbers of neutrophils, macrophages, and to a lesser degree, lymphocytes in both naïve subjects and swine confinement building workers. Interestingly, this inflammation is most pronounced in subjects with no prior exposure to this environment. This finding suggests that adaptation or tolerance to endotoxin or other substances in this environment is induced by repeated exposures. Interventions have been devised to reduce the risk of symptomatic respiratory disease from working in a swine confinement facility. The efficacy of several of these interventions was tested using objective measures of respiratory tract inflammation. Recent finding suggests that such studies should be done in swine confinement workers if they appear promising using testing of naïve subjects exposed to this environment.

Inhalation challenge with bovine dander allergens: who needs it?

STUDY OBJECTIVES

To identify which tests would be useful in selecting patients for a specific inhalation challenge with bovine dander allergens (bSIC).

DESIGN

A prospective study.

SETTING

A university hospital.

PATIENTS

Thirty-seven dairy farmers with a clinical suspicion of occupational asthma due to bovine allergens.

INTERVENTIONS

Each patient (n = 27) underwent histamine challenge, mannitol challenge, exhaled nitric oxide (NO) measurement, bovine-specific serum IgE measurement, and skin-prick test (SPT) with bovine allergens prior to undergoing a bSIC.

RESULTS

Eleven patients responded to the inhalation challenge with bovine allergens. The sensitivity and specificity of the tests, based on this response, were 82% and 65%, respectively, for the histamine challenge; 20% and 94%, respectively, for the mannitol challenge; 27% and 77%, respectively, for the NO measurement; 82% and 100%, respectively, for the bovine-specific serum IgE measurement; and 100% and 50%, respectively, for the SPT. Multiple regression analysis revealed that only IgE-mediated sensitivity to bovine allergens, but neither bronchial hyperreactivity nor exhaled NO concentration, contributed significantly to the response.

CONCLUSION

Only the SPT with bovine allergens and bovine-specific serum IgE measurements were useful in selecting patients for the bSIC. This challenge should not be performed in SPT-negative subjects. A diagnosis of occupational asthma due to bovine dander allergens could be made without an inhalation challenge test in asthmatic patients with high bovine-specific serum IgE levels. This practice would eliminate the need for the majority of bSICs.

Tetanus seroprevalence among farmers: a preliminary study

BACKGROUND

Farmers are at increased risk of contracting tetanus. However, no difference in immunity to tetanus has been reported between rural and urban dwellers in large epidemiological studies. We hypothesized that tetanus antibody concentrations would be lower in farmers than in nonfarmers within the rural population.

METHODS

We recruited 102 adult subjects attending an agribusiness trade show who identified themselves as farmers in Wisconsin. The nonfarmer group (n = 120) was composed of adults attending the agribusiness show who were not engaged in farming or were participating in another research study. Concentrations of antibody to tetanus toxin (antiTT) in sera were measured by an enzyme-linked immunosorbent assay (IBL, Hamburg). AntiTT levels of >0.15 IU/mL were considered protective.

RESULTS

The antiTT concentrations for the farmer population (median = 2.74 IU/mL) were much higher than those for the nonfarmer group (median = 1.82 IU/mL) (P<.008). As in other studies, being male, being younger, and having a history of military service were positively correlated with protective antiTT concentrations. However, only farming, age, and the farming-sex interaction term were significantly associated with antiTT concentrations in the multiple-regression model.

CONCLUSIONS

The farmers we studied had high antiTT concentrations and a high tetanus seroprevalence rate. Occupation may be an important consideration in the development of immunization policies. A broader seroepidemiological study of farmers must be undertaken before any such considerations can be made.

IgE-mediated sensitization to predatory mites in Swedish greenhouse workers

BACKGROUND

Predatory mites are used as biological pesticides worldwide for control of spider mites and other pests in greenhouses. The aim of this study was to investigate if predatory and spider mites give rise to sensitization among greenhouse workers who use biological pesticides.

METHODS

Blood samples were collected from 31 greenhouse workers from Stockholm area who were using the predatory mites Phytoseiulus persimilis and Hypoaspis miles for control of pesticides. Immunoglobulin E (IgE) binding to extracts of P. persimilis and H. miles and of the spider mite Tetranychus urticae was analysed with sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting.

RESULTS

A total of 16 workers displayed IgE antibodies to one or more of the three mite species, 32% (n = 10) to P. persimilis, 52% (n = 16) to H. miles and 26% (n = 8) to T. urticae. At least 17 IgE binding components in the molecular weight ranging from 28 to >94 kDa were identified in P. persimilis. In H. miles, at least 11 components were detected, among them at least one major component at about 70 kDa. Twenty-four IgE binding components were found in T. urticae.

CONCLUSIONS

In this study we have for the first time shown that the predatory mites P. persimilis and H. miles can cause IgE-mediated sensitization among greenhouse workers. The clinical relevance of sensitization to predatory mites needs to be investigated in further studies.

A case of primary tularemic pneumonia presenting with necrotizing mediastinal and hilar lymph nodes

Tularemia is an unusual disease caused by the gram-negative coccobacillus Francisella tularensis. The clinical features of the disease depend on the route of inoculation. Ulceroglandular and typhoidal forms have been recognized as occurring in tularemia, however primary or secondary pneumonic infections have also been reported. Symptoms, laboratory markers and radiological features are non-specific in tularemic pneumonia. Diagnosis is made on clinical grounds and evidence of elevated agglutinating antibodies to F. tularensis (> 1:128). We report a case of primary tularemic pneumonia presenting with pulmonary infiltrates and necrotizing mediastinal and hilar lymph nodes in an otherwise healthy subject from a non-endemic area. Diagnosis of tularemia was obtained serologically, and antibiotic therapy with doxycycline and streptomycin resolved symptoms and radiological abnormalities. We suggest that tularemia should be considered in the differential diagnosis of pneumonia with mediastinal and/or hilar lymphadenopathy.

Health effects of inhalation exposure to organic dust in hops farmers

Medical examinations were performed in a group of 23 hops farmers exposed to organic dust from hop (Humulus lupulus). The examinations took place in individual farms during harvesting, sorting and transporting of hop cones. As a reference group, 50 urban dwellers not exposed to organic dust were examined. There were conducted physical examinations, interviews concerning the occurrence of respiratory disorders and work-related symptoms, lung function tests, determination of cytokines concentrations, and allergological tests comprising skin prick test with 4 microbial antigens associated with organic dust, precipitin test with 12 microbial antigens, and a test for inhibition of leukocyte migration. Five farmers (21.7%) reported occurrence of work-related symptoms, including dry cough and dyspnoea. Eight farmers (34.8%) reported symptoms of chronic bronchitis. Mean spirometric values were within normal ranges. The farmers showed positive responses in precipitin test and test for inhibition of leukocyte migration to antigens of environmental microbes, mainly to the antigen of Gram-negative bacterium Pantoea agglomerans. The results showed a potential risk of occupational respiratory diseases in the population of hops farmers.

Relationship between total and allergen-specific IgE serum levels and presence of symptoms in farm workers sensitized to Tetranychus urticae

BACKGROUND

Clinical complaints in atopic subjects with asthma and rhinitis occur more frequently in the presence of high total and allergen-specific IgE serum levels. Here we report on the relationship between total and allergen-specific IgE serum levels and presence of symptoms in an unselected farmer population sensitized to Tetranychus urticae (TU).

METHODS

Farmers were recruited as previously described. Total IgE and allergen-specific IgE were measured by immunoassay in TU-positive skin prick test (SPT) farmers (n = 58) and two control groups including Dermatophagoides pteronyssinus (Dp)-positive SPT subjects (n = 40) and non-atopic, TU-negative SPT healthy farmers (n = 25).

RESULTS

Both TU+ and Dp+ subjects had significantly higher total IgE values (P < 0.001) than healthy non-atopic subjects. TU-specific IgE levels were significantly more elevated in symptomatic than non-symptomatic TU+ subjects (P = 0.028). Dp-specific IgE levels were higher in symptomatic than non-symptomatic Dp+ subjects (P = 0.003). Finally, total IgE levels were significantly higher in the symptomatic than non-symptomatic subgroups in both TU+ and Dp+ subjects (P < 0.0001 and P = 0.007, respectively). Logistic regression analysis showed that only total IgE concentrations were significant predictors of current symptoms in TU+ subjects.

CONCLUSIONS

High total IgE and allergen-specific IgE levels are associated with symptoms in TU+ subjects. Definition of their predictive value requires further studies.

Associations of dichlorodiphenyltrichloroethane (DDT) 4.4 and dichlorodiphenyldichloroethylene (DDE) 4.4 blood levels with plasma IL-4

DDT (dichlorodiphenyltrichloroethane) reportedly induces cancer in animals, mimics estrogen activity, induces antiandrogen effects, and impairs Natural Killer (NK) cells and T lymphocyte responses. In this study, the authors attempted to determine associations of DDT, dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) blood levels with several immune parameters in patients occupationally exposed to insecticides. The study subjects were 49 patients who worked as farmers or farmhands in the former German Democratic Republic and who had been occupationally exposed to insecticides for at least 6 mo; 80% of them had been exposed for more than 20 yr. Blood levels of DDT, DDE, DDD, 2,3,4,5,6-pentachlorophenol (PCP), polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), and gamma-hexachlorocyclohexanes (HCHs) were determined, and blood lymphocyte subpopulations, in vitro responses to mitogens or pooled allogeneic stimulator cells, plasma neopterin, and cytokine and soluble cytokine receptor levels were studied. The majority of patients were contaminated with more than 1 chemical--most commonly DDE, PCBs, and HCB. Linear-regression analysis showed that interleukin-4 (IL-4) plasma levels were associated with plasma levels of DDT 4.4 (p = .0001) and DDE 4.4 (p = .001). The data in this study suggest that PCBs, PCP, HCB, HCHs, DDE, and DDD suppress TH1 cytokines, such as IL-2 and interferon-gamma (IFN-gamma), and induce TH2 cytokines, such as IL-4. The authors hypothesized that clinical symptoms, such as the frequent infections reported by many patients, could be a consequence of these immunological abnormalities.

Threshold levels of purified natural Bos d 2 for inducing bronchial airway response in asthmatic patients

BACKGROUND

Provocation tests are invaluable in establishing threshold levels and a causal relationship between atopic asthma and a certain allergen source, especially in relation to work-associated exposure. Purified major allergens open possibilities for a more accurate assessment of sensitization.

OBJECTIVE

To determine the threshold dose of purified major bovine dander allergen Bos d 2 in bronchial provocation in comparison with the standard allergen and a set of other parameters of allergy.

METHOD

Nine consecutive patients referred to hospital for confirming the bovine origin of their occupational asthma were subjected to bronchial provocation tests with purified natural Bos d 2 and a standard bovine dander allergen. Additional tests included bronchial histamine challenge, measurements of total IgE, specific IgE antibody determinations and skin prick tests (SPT) with both allergens.

RESULTS

In the provocation tests with Bos d 2, a 15% decrease in the forced expiratory volume in 1 s (FEV1) and/or peak expiratory flow (PEF) values in eight out of nine patients confirmed the predominant role of Bos d 2 in the sensitization. The threshold dose of Bos d 2 varied from 0.1 microg to > 100 microg (median +/- median absolute deviation = 4.5 +/- 3.9 microg). A positive SPT was induced by a median dose of 13.9 +/- 9.8 microg of Bos d 2. Bronchial response to histamine and IgE antibodies against Bos d 2 showed the highest correlations to the provocations results.

CONCLUSIONS

The efficacy of Bos d 2 in bronchial provocation in patients with occupational cattle-associated asthma was confirmed and the range of the threshold level was determined. There were individual variations, but the response in provocation remains the reference method for identification of the cause of occupational atopic asthma. SPT and the measurement of specific IgE antibodies, preferably with purified or recombinant major allergens, increase the accuracy of the diagnosis.

Hypersensitivity pneumonitis induced by the spore of Pleurotus Eryngii (Eringi)

We reported the first case of hypersensitivity pneumonitis (HP) by an edible mushroom, Pleurotus Eryngii (Eringi). A 54-year-old woman had worked in a Bunashimeji mushroom factory for 42 months, and she moved to a new factory producing Eringi. Two months after, she was found to have HP by the spore of Eringi. Although no radiological finding was detected 6 months before the onset of HP, serum surfactant protein D (SP-D) had been elevated. We speculated that type II pneumocyte activation might prepare the ground for HP during the former exposure to Bunashimeji, and serum SP-D levels might reflect their conditions.

Cutaneous protothecosis: report of five cases

Prototheca, a genus of achlorophyllic algae, is a rare cause of opportunistic infection in humans. About 80 human cases, mostly cutaneous infection caused by P. wickerhamii, have been reported world-wide. We describe the clinicopathological findings and treatments of five cases diagnosed in our department during the period 1991-97. The patients, including four elderly farmers, presented with pyoderma-like lesions or infiltrating papules and plaques on the extensor side of the extremities or face. All patients were immunocompromised, mostly due to systemic or topical steroids. The diagnosis was made in each case by finding typical endospores with morula-like structures in skin biopsy specimens. P. wickerhamii was isolated in four cases in which pretreatment culture of skin tissue was done. Except for one patient who died of asthma, the infection was cured after 2-7 weeks of amphotericin B, ketoconazole, itraconazole or fluconazole. Our cases illustrate that cutaneous protothecosis commonly manifested non-tender, pyoderma-like or infiltrating lesions and should be considered in the differential diagnosis of deep fungal or mycobacterial infection. This rare infection seemed more frequent in our region, possibly due in part to common steroid abuse among old people in Taiwan and there was a large population of elderly farmers in our area.

[Sensitization to cow and pig allergens among farmers in Eastern Poland]

The study aimed at assessing the frequency of sensitization to cow and pig allergens among farmers in Eastern Poland. Sixty eight farmers from 17 randomly selected family farms were examined. The study group included 30 females and 38 males, aged 18-84 years (median, 47 years), with exposure duration ranging from 1 to 80 years (median, 30 years). The farmers were interviewed and subsequently skin prick-tested with cow and swine epithelia. Blood samples were examined for the presence of IgE antibodies, specific to cow dander and swine epithelium, using enzyme immunoassay (UniCAP). None of the farmers complained of any symptoms when working with cows or pigs. In 13 farmers (19.1%) either positive skin pick test and/or the presence of IgE specific to cow and/or pig were found. Seven farmers (10.3%) reacted to skin prick tests: 2 to cow epithelium; 2 to pig epithelium; and 3 to both allergens. Specific IgE was also found in 7 farmers (10.3%): in 4 to cow dander; in 1 to cow epithelium; and in 2 to both allergens. There was a very weak correlation between skin tests and IgE determination; only one farmer showed positive reaction to cow allergens in both skin tests and IgE. Following the results of the previous and the present studies, it was concluded that in Poland the farm animal allergens are less important causes of work-related diseases than plant allergens.

[Sensitization and occupational asthma in poultry workers]

BACKGROUND

A high prevalence of asthma has been reported in poultry farmers. Our aim was to determine air contaminants in poultry confinement buildings and the prevalence of occupational asthma in these workers.

PATIENTS AND METHOD

Spanish poultry farmers who participated in the European Study Prevalence and Risk Factors for Airway Obstruction in Farmers, who worked inside confinement buildings, were enrolled in a cross-sectional study that included the measurement of air contaminants (ammonia, total dust, endotoxin and microorganisms), symptoms, skin testing with common and poultry-related allergens, and a specific bronchial challenge. The Spearman correlation coefficient was used to assess the correlation between air contaminants.

RESULTS

14/15 poultry farmers participated in the study (response index: 93.3%). Concentrations of air contaminants in the confinement buildings [median (interquartile range)] were: 7.5 (5-20) ppm for ammonia, 2.6 (1.8-4.6) mg/m3 for total dust, 137.1 (58.6-243.9) ng/m3 for endotoxin and 7,600 (907-27,750) colony-forming units/m3 * 103 for bacteria. Endotoxin correlated with bacterial concentration (r = 0.69, p < 0.01). 5/14 poultry farmers reported wheezing and/or asthma within the last year (35.7%), and in 2 of them spirometry demonstrated current asthma (14.3%). Specific bronchial provocation confirmed the diagnosis of occupational asthma in one subject with current asthma sensitized to the storage mite Lepidoglyphos destructor (7.1%).

CONCLUSIONS

One third of poultry farmers working inside confinement buildings reported wheezing, that is partly attributable to occupational asthma caused by storage mites.

[Seroprevalence of brucellosis in agricultural workers in the coastal zones of Castellón, Spain]

OBJECTIVE

To estimate the seroprevalence of brucellosis in agricultural workers.

MATERIAL AND METHODS

This cross-sectional study was conducted between 1996 and 1997 at Unidad de Salud Laboral del Centro de Salud Pública (CSP) in Castellón, España (Public Health Center Occupational Health Unit), among 482 subjects applying for certification to handle pesticides for agricultural use. Serologic testing consisted of rose Bengal staining, Wright's agglutination, and antibrucella Coombs tests: Statistical analysis consisted in estimation of prevalence figures and logistic regression modelling.

RESULTS

Fifteen subjects (3.1%, 95% CI 1.8%-5.1%) had titers of 1/40 or higher to Wright and/or Coombs tests; all were negative to rose Bengal staining. No high occupational risk was observed.

CONCLUSIONS

A low prevalence of brucellosis was found. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

Precipitin response of potato processing workers to work-related microbial allergens

Serum samples from 61 potato processing workers and 30 urban dwellers not exposed to organic dusts (as a reference group) were examined in agar-gel precipitation test performed by Ouchterlony double diffusion method with the antigens of 12 microorganisms associated with organic dusts. Each serum was tested twice: not concentrated, and three-fold concentrated, for the detection of low levels of precipitins. The antibody response of workers to the antigen of coryneform bacterium Agromyces ramosus was high, at both not concentrated and 3-fold concentrated sera (respectively 29.5% and 45.9%)--significantly greater than in reference group (p < 0.001). Workers' response to the antigens of Gram-negative bacterium Alcaligenes faecalis and thermophilic actinomycete Thermoactinomyces vulgaris was lower (respectively 13.1% and 13.1% at not concentrated sera, 24.6% and 29.5% at 3-fold concentrated sera) but in all cases significantly greater than in reference group (p < 0.05 at not concentrated sera, p < 0.01 and p < 0.001 at 3-fold concentrated sera). The frequency of positive precipitin reactions of potato workers to antigen of Penicillium citrinum was high only at 3-fold concentrated sera (55.7%)--significantly higher compared to reference group (p < 0.001). The antibody response of potato workers to other antigens was either unspecific or low, showing no significant difference compared to reference group. Twenty eight out of 61 examined potato processing workers (45.9%) reported the occurrence of the work-related pulmonary symptoms. The frequency of positive precipitin reactions to Agromyces ramosus, Alcaligenes faecalis, Thermoactinomyces vulgaris, Penicillium citrinum and Acinetobacter calcoaceticus was significantly greater in the subgroup of 28 workers reporting work-related pulmonary symptoms compared to 33 asymptomatic workers (p < 0.05). Study results suggest that antigens of Agromyces ramosus, Alcaligenes faecalis, Thermoactinomyces vulgaris and Penicillium citrinum should be considered as potential occupational allergens, probably stimulating an adverse immunopathological reaction in the exposed potato processing workers.

Does environmental endotoxin exposure prevent asthma?

The evidence as to whether exposure to environmental airborne endotoxin plays a protective or an inducing role in the development of asthma is reviewed. Studies of endotoxin and atopy, endotoxin and asthma, and farming and asthma are considered and, in each instance, a distinction is made between evidence of primary causation and evidence of secondary causation. It is concluded that, although it is plausible that bacterial endotoxin may protect against the development of asthma, there is considerable reason for caution regarding this hypothesis.

Sensitization to sunflower pollen and lung functions in sunflower processing workers

BACKGROUND

This study aimed to investigate whether exposure to sunflower pollen (Helianthus annuus) increases both sensitization and respiratory symptoms, and whether or not it affects lung functions in sunflower processing workers.

METHODS

The largest sunflower processing factories in the Thrace region of Turkey participated in this study. Workers from the units directly exposed to sunflower seed enrolled as the study group (n = 102) and workers who were not directly exposed to Helianthus annuus pollen (n = 102) were the control group. Detailed questionnaires covering respiratory and allergic symptoms were completed, and skin prick tests and lung function tests were performed.

RESULTS

We found a very high rate (23.5%) of sensitization to Helianthus annuus in the study group compared to the controls (P<0.001). Logistic regression analysis showed that the risk of sensitization to H. annuus was increased 4.7-fold (odds ratio = 4.17, 95%) confidence interval = 1.3-16.7) if subjects were exposed to sunflower pollen in the workplace. While asthmatic symptoms and allergic skin diseases were not different between the two groups, workers in the study group had a higher rate of allergic rhinitis and conjunctivitis (P<0.05). We found that pulmonary function was significantly impaired in the study group (P<0.01). Using a multivariate analysis model, inclusion in the study group was found to be a predictive factor for impairment of lung function (P=0.002).

CONCLUSIONS

We conclude that sunflower pollen has high allergenic potential, especially when there is close contact, and exposure to sunflower pollen in the workplace can result in impairment in lung function.

Longitudinal changes of sensitization to farming-related antigens among young farmers

BACKGROUND

We have shown previously that the prevalence of allergic sensitization in Tyrolean farming students is high, with a clear relationship to occupational exposure.

OBJECTIVES

It was the aim of this investigation to assess longitudinal changes in sensitization and a possible impact on lung function.

METHODS

Of the 147 farming students in the original cohort, we could re-examine 42 after a mean interval of 4.0 years. All individuals completed a questionnaire and had spirometry, skin prick tests, total and specific IgE analysis, and testing for precipitating antibodies.

RESULTS

As compared to the first study, there was a decrease in the frequency of IgE-mediated allergy (30.1 vs. 54.8%; p < 0.05) and in total serum IgE levels (107.4 +/- 254 vs. 157.8 +/- 304 U/ml; p < 0.001). Conversely, 3 individuals had developed precipitating antibodies de novo, and those who had initially had a positive precipitin test (n = 6) were still positive. A larger-sized estate, the lack of a hay dryer, and the presence of moldy hay were confirmed as risk factors for allergic sensitization. Although there was a slight overall decrease in forced vital capacity, no new cases of occupational lung disease were found.

CONCLUSIONS

In young Tyrolean dairy farmers, the prevalence of precipitins is constantly high and rising while IgE-mediated allergy declines. Within 4 years, no clinically relevant impact of allergy on lung function was noticed.